Muscles that control motion of the fingers are physiologically capable of more precise motion than muscles that control the wrist or forearm. Devices that are designed for manipulation by the fingers allow physicians to use optimum dexterity and control during delicate surgical procedures such as microsurgery and laparoscopy. These procedures require the use of devices with jaws or blades that are precisely controllable for preventing damage to tissue adjacent the treated site. Furthermore, the devices should be convenient to use for minimizing operative time and muscle fatigue of the physician. To date, surgical devices that are readily and precisely controlled by the muscles of the fingers are very limited.
One prior art device has a scissors-type grip for actuating a sliding cable or link within a flexible casing to open or close cooperating jaws or blades. A problem with this device is that the rotation thereof requires turning the grip using muscles of the wrist. Another problem with this device is that the device is not rotatable about the axis of the device casing unless the casing is maintained perfectly straight. These problems limit the physician's degree of control over the device. Yet another problem with this device is that the working head is not fixedly positioned with respect to the axis of the device. The working head may nutate when the device is rotated, thereby damaging tissue adjacent the treatment site. Still another problem with the device is that maintaining closure of the jaws or blades requires constant pressure on the grip, which is awkward and inconvenient for a physician during a procedure. In addition, applying constant pressure to the grip causes muscle fatigue and further loss of control over the device.
Another nonsurgical device as disclosed in U.S. Pat. No. 273,243 of Adams is a pair of pivotally interconnected tongs that are spring-biased closed for grasping and holding an object. The tongs are actuated open by depressing a control rod on the proximal end of a handle for compressing the spring. A problem with this device is that the actuation portion of the working head is not designed for use in delicate medical procedures. For example, the actuation portion includes interconnecting links that extend between several pivot pin connections. The links project laterally at abrupt angles when the tongs are actuated. These lateral projections may damage tissue adjacent the treated site. In addition, the working head is easily nutated when the device is rotated or positioned at an acute angle with respect to the object to be grasped. Furthermore, grasping of the object and subsequent manipulation requires repositioning of the hand about the proximal end of the device. As a result, the instrument can not be controlled with the finesse and delicacy required for surgical procedures.
Another device as disclosed in U.S. Pat. No. 3,506,012 of Brown is a surgical instrument for removing a polyp by connecting and disconnecting a distal clamp unit. The device includes a longitudinally actuated control rod, which also rotates for opening and closing a pair of distal pivoted jaws. A problem with this device is that actuating the jaws requires two-hand manipulation. The tubular device body is firmly gripped by one hand so that a hand knob on the control rod is rotated to open or close the distal jaws. The control rod is pulled rearwardly for releasing the clamp unit. The use of two hands to manipulate the device is inconvenient for a physician and may lengthen the operative time of some procedures. Furthermore, using the muscles of the wrist and forearm diminishes the precision and control a physician has over the device, and adjacent tissue may be inadvertently damaged.
Another nonsurgical device as disclosed in U.S. Pat. No. 4,039,216 of Soos is a gun-grip grasping device with a manually operated lever that is pulled toward a fixed handle for closing two distal jaws and retrieving articles from the ground without bending over to pick them up. A problem with this device is that the device is actuated using the muscles of a closing hand rather than one or two fingers. Another problem with the device is that the jaws remain open when nonactuated. Furthermore, the operator has to maintain pressure on the lever to hold the jaws closed, which causes muscle fatigue.
Another prior art surgical device as disclosed in U.S. Pat. No. 4,760,848 of Hasson includes a working head with pivotally interconnected jaws and an actuating link for moving the element by pressing laterally with the thumb and finger of one hand on the control elements of a casing. Although suited for its intended purpose, this device during repeated actuation quickly fatigues the muscles of the physician's fingers. Furthermore, control of the device is compromised during actuation and even more so during repeated actuations.